Technical Field
The present invention concerns a lifting beam for lifting and handling a rotor blade as well as a handling arrangement with a lifting beam and a rotor blade for handling a rotor blade. The invention also concerns a transport apparatus for transporting a lifting beam, a method of fitting rotor blades, a method of fitting a rotor, a method of removing rotor blades and a method of replacing rotor blades.
Description of the Related Art
Wind power installations have long been known and a common type is a so-called horizontal-axis wind power installation as is also shown in FIG. 1. A horizontal-axis wind power installation or a wind power installation with a horizontal-axis rotor denotes an arrangement with a horizontal rotor axis, to distinguish it from a type with a vertical rotor axis. An exactly horizontal orientation of the rotor axis is not an important consideration, but the aim is only to denote the basic type of installation. Nowadays conventional horizontal-axis wind power installations have three rotor blades, and the invention hereinafter is concentrated thereon without being restricted thereto. Insofar as details hereinafter make sense only in connection with a horizontal-axis rotor with three rotor blades, it is to be correspondingly assumed that this involves a rotor having three rotor blades.
To install a wind power installation it was usual for the rotor with the rotor blades to be prefabricated on the ground at the location of erection of the wind power installation, namely to fix the rotor blades to the rotor hub. The rotor prefabricated in that way was then lifted off the ground in particular at the rotor hub together with the rotor blades fitted thereto and fixed to a pod which was already mounted on a mast or pylon, without the rotor.
With an increasing size of wind power installations and thus an increasing rotor blade length such a kind of fitment procedure is found to be more and more difficult. Thus for example the rotor of an Enercon E126 wind power installation is of a diameter of 126 meters (m). Handling a rotor of that size is difficult and makes high demands in particular on the crane. Besides the geometrical dimensions, such a rotor is also of an enormous mass and thus enormous weight. Added to that is the fact that, in the case of such modern large wind power installations, the pylon is even higher and in particular the installed axis height is very high. Thus a wind power installation from Enercon of type E126 can involve an axis height of over 130 m, which corresponds to three times the height of the sailing school ship Gorch Fock.
In particular the height to which a component to be fitted has to be lifted and also the load thereof quite substantially determine the required crane and thus its costs. An additional height of a few meters can sometimes mean that a crane of a next higher category is required. In that respect the cranes used for erecting large modern wind power installations like the E126 already nowadays belong to the category of the largest available truck-mounted cranes.
If a rotor blade is installed individually on a rotor hub which has already been fitted to the pod then in corresponding fashion it is only the weight of that one rotor blade that needs to be lifted. Thus for example a rotor blade can be fitted vertically from below to a suitably oriented rotor hub. In the case of a three-blade rotor however the other two positions for the other two rotor blades are then at a high position. To install the two rotor blades therefore the respective rotor blade would have to be lifted to a corresponding height, namely higher than the axis of the rotor, or the rotor hub would have to be rotated.
That rotation of the rotor hub with a rotor blade installed thereon however requires a correspondingly great force to lift the rotor blade which has already been installed, in a rotary movement. In principle such a rotation can be implemented by means of the generator operating in a motor mode. For that purpose however a suitable installation of the generator would be required at that early stage in construction, including linking it to the power supply network into which the generator feed is later to occur in order to take energy for that motor mode. In addition the generators would have to be suitably supplied with energy for that specific task and appropriately controlled.
As general state of the art attention is directed to the documents EP 2 003 333 A1, DE 10 2008 033 857 A1, DE 20 2010 003 033 U1, DE 201 09 835 U1 and DE 103 05 543 C5.